Format codegen with rustfmt 0.9.0
diff --git a/codegen/src/main.rs b/codegen/src/main.rs
index 89eec81..ed6bfc8 100644
--- a/codegen/src/main.rs
+++ b/codegen/src/main.rs
@@ -623,10 +623,7 @@
                 ty = ty,
                 name = name.tokens(),
             ),
-            Visit => format!(
-                "tokens_helper(_visitor, &({name}).0)",
-                name = name.tokens(),
-            ),
+            Visit => format!("tokens_helper(_visitor, &({name}).0)", name = name.tokens(),),
             VisitMut => format!(
                 "tokens_helper(_visitor, &mut ({name}).0)",
                 name = name.tokens(),
@@ -754,8 +751,7 @@
                                     Ident::new(&name, Span::call_site()).to_tokens(&mut tokens);
 
                                     (el, tokens)
-                                })
-                                .collect();
+                                }).collect();
 
                             state.visit_impl.push_str(") => {\n");
                             state.visit_mut_impl.push_str(") => {\n");
@@ -831,8 +827,7 @@
                             .map(|el| {
                                 let id = el.ident.clone();
                                 (el, quote!(_i.#id))
-                            })
-                            .collect()
+                            }).collect()
                     }
                     Fields::Unnamed(ref fields) => {
                         state
@@ -845,13 +840,14 @@
                             .map(|(idx, el)| {
                                 let id = Index::from(idx);
                                 (el, quote!(_i.#id))
-                            })
-                            .collect()
+                            }).collect()
                     }
                     Fields::Unit => {
                         if s.ast.ident == "Ident" {
                             state.fold_impl.push_str("    let mut _i = _i;\n");
-                            state.fold_impl.push_str("    let span = _visitor.fold_span(_i.span());\n");
+                            state
+                                .fold_impl
+                                .push_str("    let span = _visitor.fold_span(_i.span());\n");
                             state.fold_impl.push_str("    _i.set_span(span);\n");
                         }
                         state.fold_impl.push_str("    _i\n");
@@ -967,8 +963,10 @@
 }
 ";
 
-    write_file(FOLD_SRC, format!(
-        "\
+    write_file(
+        FOLD_SRC,
+        format!(
+            "\
 // THIS FILE IS AUTOMATICALLY GENERATED; DO NOT EDIT
 
 // Unreachable code is generated sometimes without the full feature.
@@ -1021,13 +1019,16 @@
 
 {fold_impl}
 ",
-        full_macro = full_macro,
-        fold_trait = state.fold_trait,
-        fold_impl = state.fold_impl
-    ));
+            full_macro = full_macro,
+            fold_trait = state.fold_trait,
+            fold_impl = state.fold_impl
+        ),
+    );
 
-    write_file(VISIT_SRC, format!(
-        "\
+    write_file(
+        VISIT_SRC,
+        format!(
+            "\
 // THIS FILE IS AUTOMATICALLY GENERATED; DO NOT EDIT
 
 #![cfg_attr(feature = \"cargo-clippy\", allow(match_same_arms))]
@@ -1054,13 +1055,16 @@
 
 {visit_impl}
 ",
-        full_macro = full_macro,
-        visit_trait = state.visit_trait,
-        visit_impl = state.visit_impl
-    ));
+            full_macro = full_macro,
+            visit_trait = state.visit_trait,
+            visit_impl = state.visit_impl
+        ),
+    );
 
-    write_file(VISIT_MUT_SRC, format!(
-        "\
+    write_file(
+        VISIT_MUT_SRC,
+        format!(
+            "\
 // THIS FILE IS AUTOMATICALLY GENERATED; DO NOT EDIT
 
 #![cfg_attr(feature = \"cargo-clippy\", allow(match_same_arms))]
@@ -1088,8 +1092,9 @@
 
 {visit_mut_impl}
 ",
-        full_macro = full_macro,
-        visit_mut_trait = state.visit_mut_trait,
-        visit_mut_impl = state.visit_mut_impl
-    ));
+            full_macro = full_macro,
+            visit_mut_trait = state.visit_mut_trait,
+            visit_mut_impl = state.visit_mut_impl
+        ),
+    );
 }